164 TRANSFORMATION OF ANIMALS. 



kind of box, which covers and defends its whole body. It ac- 

 complishes this purpose by moistening, for some moments, the 

 pieces of wood in its mouth, and then attaches them to each 

 other by a glutinous substance. Of this mixture the cater- 

 pillar forms a cod, the solidity of which is nearly equal to that 

 of wood. 



The most solitary of all insects are those which live in the 

 internal parts of fruits. Many of them undergo their meta- 

 morphosis in the fruit itself, which affords them both nourish- 

 ment and a safe retreat. They dig cavities in the fruit, which 

 some of them either line with silk, or spin cods. Others leave 

 the fruit, and retire to be transformed in the earth. 



The metamorphosis of insects has been regarded as a sud- 

 den operation, because they often burst their shell or silky 

 covering quickly, and immediately appear furnished with 

 wings. But, by more attentive observation, it has been dis- 

 covered that the transformation of caterpillars is a gradual 

 process from the moment the animals are hatched till they ar- 

 rive at a state of perfection. Why, it may be asked, do 

 caterpillars so frequently cast their skins? The new. skin and 

 other organs were lodged under the old ones, as in so many 

 tubes or cases, and the animal retires from these cases, be- 

 cause they have become too strait. The reality of these 

 encasements has been demonstrated by a simple experiment. 

 When about to moult or cast its skin, if the foremost legs of 

 a caterpillar are cut off, the animal comes out of the old skin 

 deprived of these legs. From this fact, Reaumur conjectured 

 that the chrysalis might be thus encased and concealed under 

 the last skin of the caterpillar. He discovered that the 

 chrysalis, or rather the butterfly itself, was enclosed in the 

 body of the caterpillar. The proboscis, the antennae, the 

 limbs, and the wings of the fly, are so nicely folded up, that 

 they occupy a small space only under the two first rings of 

 the caterpillar. In the first six limbs of the caterpillar are 

 encased the six limbs of the butterfly. Even the eggs of the 

 butterfly have been discovered in the caterpillar long before 

 its transformation. 



From these facts, it appears that the transformation of in- 

 sects is only the throwing off of external and temporary cov- 

 erings, and not an alteration of the original form. They live 

 and receive nourishment in envelopes, till they acquire such a 

 degree of perfection as enables them to support the situation 

 to which they are ultimately destined by nature. 



Transformations are not peculiar to animals. All organized 



